What’s Vulnerable › Vulnerabilities

CVE-2026-43827: Apache Shiro: Session fixation: new session is not created after login by default

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-25 · updated 2026-07-24
• Weakness: CWE-384

Description

Default configurations of Apache Shiro have a session fixation vulnerability. This issue affects Apache Shiro from 1.0 to 2.1.0, and 3.0.0-alpha-1. Users are recommended to upgrade to version 2.1.1, or 3.0.0-alpha-2 or later, which fixes the issue. In the affected versions, when a session already exists, it is not invalidated upon successful login, nor is a new session being generated with a new ID.

Affected products

• Apache Software Foundation Apache Shiro: before 2.1.1; 3.0.0-alpha1 — fixed in 2.1.1

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Shiro 2.1.1. Check the vendor advisory for mitigations.

References

• https://shiro.apache.org/security-reports.html#cve_2026_43827
• http://www.openwall.com/lists/oss-security/2026/05/25/6

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